1. Field of the Invention
The present invention generally relates to a selective calling receiver, and in particular to a method and system for managing received messages which are stored in a message memory.
2. Description of the Related Art
A selective calling receiver has been widely used for various purposes and, especially, a small-sized and lightweight selective calling receiver called a pager is suitable for being taken on the road. A basic function of the selective calling receiver is to indicate by beep sound, vibration, or light the incoming call and then to display a received message on an liquid-crystal display (LCD). The received message is first stored in a message memory and is then read out from the message memory to be displayed on screen according to user's key operations. Since a plurality of received messages are usually stored in the message memory, message management becomes important.
A message management scheme in a paging system has been disclosed in Japanese Patent Unexamined Publication No. 60-197029. In this paging system, a center system has the message management function including a selective calling data storage function, a calling time management function, and a selective calling data transmission control function. Another message management scheme in a paging system has been disclosed in Japanese Patent Unexamined Publication No. 2-200050. This system is provided with a message storage unit having message storage areas and a controller. The controller searches the message storage areas for all messages addressed to a receiving terminal and sends them to the terminal.
However, such a message management scheme mentioned above is not implemented in a receiving terminal or a pager but at the center system. In a receiving terminal, a received message is stored into the message memory until the message memory becomes full. When the message memory reaches capacity, the oldest message is automatically deleted from and the latest is stored into the message memory. Therefore, a necessary message may be deleted without knowledge of the user. On the other hand, in the case where a necessary message is protected, the message is stored in the message memory for indefinitely long time periods until it is deleted by the user consciously, resulting in unnecessarily reduced memory area.